Date   : Wed, 26 Oct 1983 12:07:34 EDT
From   : Keith Petersen <w8sdz@brl>
Subject: Re: Request for help (long msg)

This sounds to me like a DCD (Data Carrier Detect) status problem.
After the modem has hung up and there is no longer any carrier,
DCD goes low (unless you have done something with the status
option switches on your Hayes Smartmodem to bypass this).  It may
be that your Interfacer I/O board is set up so that if it does
not have DCD it will not receive characters coming in.  Many serial
cards do this, ignoring input until some external status line line
DSR (Data Set Ready) or DCD (Data Carrier Detect) comes "on".
The reason your terminal works direct is that it's probably
set up to not require these status signals.
--Keith